Analogue output modules 8 bits
System Catalogue : PCD3
|Extract||PP26-215_A0120||System Catalogue : PCD3|
PCD3.W400 - Analogue outputs, 4 channels, 8 bits
|Datasheet||31-641||PCD3.W400 - Analogue outputs, 4 channels, 8 bits|
PCD3.W410 - Analogue outputs, 4 channels, 8 bits
|Datasheet||31-642||PCD3.W410 - Analogue outputs, 4 channels, 8 bits|
Systemcable and adapter
|Manual||26-792||Systemcable and adapter|
Software / Tools
PCD3 / Wxxx
Why do the 0 to 10 V analog outputs of the PCD3.W800 cards 'freeze' to a random value during operation and cannot be controlled by the user program? (FAQ #102028)
It may happen that the 0..10V analog outputs of the PCD3.W800 cards 'freeze' to a random value during operation and cannot be controlled by the user program.
We are currently analyzing the trigger for freezing the analog outputs of the PCD3.W800 module so that we can inform you if your application is affected by the problem.
This FAQ will be dated as soon as we have new information.
PCD3.W800 cards manufactured between 1801 and 1834.
The manufacturing date is marked on the white sticker on the right side of the PCD3.W800 module.
At any time the analog outputs of the affected PCD3.W800 cards can 'freeze' at any value between 0 and 10V and it is no longer possible to change the analog output from the user program.
The manual operation of the analog outputs 0 to 2 still works with the manual switch and the corresponding potentiometer.
The malfunction occurs regardless of whether the PCD3.W800 module has been configured with FBoxes in the PG5 user program or with the PG5 device configurator.
If one of the analog outputs of the PCD3.W800 module freezes, the 24VDC power supply of the PCD3 must be switched off and on again.
After that the control of the analog outputs of the PCD3.W800 works normally again.
For critical applications where this malfunction can cause considerable damage, we recommend either:
- the exchange of the affected PCD3.W800 modules with new modules (manufacturing date 1835 or newer)
- the use of another 0..10 V analog output module such as PCD3.W500, PCD3.W600 or PCD3.W605.
To replace the affected modules:
Order the desired number of PCD3.W800 modules or the other PCD3 analog output modules from SBC and send the affected modules back to SBC via RMA.
In the RMA form, note 'Advance exchange' with the remark '8D-SBC-18-027'.
The affected PCD3.W800 modules will then be credited to you.
Why do the output of the PCD2/3.W6x5 not deliver stable signals? (FAQ #102014)
Depending of the hardware version of the W6x5 module and the I/O slot where the W6x5 module is plugged in, it’s possible that the analog output signal supplied from the W6x5 is not stable and is oscillating.
The outputs of the PCD2/3.W6x5 do not deliver stable signals when placed on I/O slot 15 if hardware version B of the W6x5 is used.
If FBoxes are used for writing to the outputs, the FBox indicates temporarily an error.
The W6x5 modules with hardware version B are not correctly handling the Watchdog output (O 255).
Note that this is only the case if the module is placed on I/O slot 15 (base address 240). On all other slots the modules work correctly.
This problem is solved with hardware version A or C and newer of the PCD2.W6x5 or PCD3.W6x5 respectively.
How to read the diagnostic information of a PCD3.W745 on a PCD3.T760? (FAQ #101697)
When the 4 channels analog carte PCD2.W745 is used on a PCD3.T760 RIO module 6 registers are available on the master station. It is important to know that the 2 first registers contain the diagnostic bits of the 4 inputs channels!
How to interpret those 2 diagnostic registers (anal_16 and anal_17) ?
The first 2 bytes (low bytes) gives the diagnostic bit of 2 analog channels (1 byte per channel) as indicated in the following screenshot:
Signification of each bit (from right to left):
Why are analogue entries of the PCD3.W745 displayed incorrectly when using the memory mapping? (FAQ #101672)
The analogue entries of the PCD3.W745 card aren't displayed correctly when using the memory mapping of the PG5 2.0 SP2 Device Configurator. On the other hand everything is running fine when I use the FBox "PCD3.W745" from Fupla.
The analogue entries of the PCD3.W745 card aren't displayed correctly when using the memory mapping of the PG5 2.0 SP2 Device Configurator.
There's an error in allocating the address mapping of the Device Configurator in PG5 2.0.200 (SP2) for this analog card PCD3.W745.
This problem will be solved in PG220.127.116.11.0.
What is the signification of the I/O words of a PCD2/3.W525 module? (FAQ #101552)
When configuring a W525 module using the Device Configurator or the Profi-S-I/O (or Profibus DP) Network Configurator, the PCD2/3.W525 does need two registers for the analogue outputs and 8 registers for the analogue inputs.
The significations of the registers are the following:
Value CH0 Output
Value CH1 Output
Description of the output registers:
Value CH0..1 (Register n, n+1)
This registers (Bit 0 to 15) does contain the analogue output value of the corresponding analogue output. It's a 12 Bit value.
Value CH0 Input
Value CH1 Input
Value CH2 Input
Value CH3 Input
Description of the input registers:
Value CH0..CH3 (Register n...n+3)
This registers (Bit 0 to 15) does contain the analogue input value of the corresponding analogue input. It's a 14 Bit value.
Load_Current / Load_Voltage (Register n+4)
On this register (Bit 0 to 15) the actual current or voltage value is displayed.
- current in [μA] (0..20'000)
- voltage in [mV] (0..10'000)
Status Module (Register n+5)
This register (Bit 0 to 15) does contain the actual status of the module
Table module status:
Error on the output channel CH1
Error on the output channel CH0
Error on the input channel CH3
Error on the input channel CH2
Error on the input channel CH1
Error on the input channel CH0
Communication: Illegal Command.
Is set to 1 if the module receive a not know instruction.
Communication: packet too long.
Is set to 1 if during the communication a data byte
(CMD/Data = 0) is received although a commando byte should be received (CMD/Data = 1)
UExt too low.
The voltage of the external power supply is to low!
Status Input (Register n+6)
This register (Bit 0 to 15) does contains the status of the input channels CH0..CH3.
The status of each input channel is displayed on 4 bits.
Table input status:
Status Output (Register n+7)
This register (Bit 0 to 15) does contain the status of the two output channels CH0 and CH1.
The status of each output channel is displayed on 6 bits.
CH0 Status (LOW BYTE)
CH1 Status (HIGH BYTE)
Table output status:
Load Resistance too high.
Only for outputs in current mode.
Occurs typically if the output circuit is open
Load Resistance too low.
Only for outputs in voltage mode.
Occurs typically in case of short circuit
Why do I get wrong values when reading a PCD2/3.W340 with media mapping? (FAQ #101416)
PCD2.M5xx0 and the PCD3.Mxxx0 systems equipped with firmware 1.10.16 did not correctly calculate the temperature values of NI1000 temperature sensors measured with PCD2/3.W340 input modules.
The temperature read by the media mapping for Ni1000 sensors which are connected to a PCD2.W340 or a PCD3.W340 installed on a PCD3 or a PCD2.M5 is not correct with firmware version 1.10.16.
The firmware did not correctly convert the measured signals to the according temperature.
Please update the firmware of your PCD to version 1.10.51 or later.
What exactly is a PCD2/3.W721 and can I order it? (FAQ #101247)
When the weighing modules first have been introduced it was possible to order a weighing module that was already calibrated for a specific weighing cell. This module was a PCD2.W721 (or PCD3.W721).
After gathering some experiences it turned out that such a calibration of a module is only asked very seldom. Beside of this fact it showed that better calibration results can be achieved when directly calibrating the module in the target system.
Due to these facts it has been decided to remove the PCD2/3.W721 from the price list. It is no longer possible ordering this module (instead, use a PCD2/3.W720).
Why do the outputs of PCD2/3.W525 not work? (FAQ #101204)
The outputs of a PCD2.W525 or a PCD3.W525 need to be configured correctly. If this is the case, it is possible that a problem in the FBox leads to the fact that the outputs are not written correctly.
The output signal of a W525 module is always 0. At the same time, the inputs of the FBox do work correctly.
This phenomenon can be caused by either
- an incorrect configuration in the FBox
- the module has no power supply connected. In this case the LED on the module is blinking
- a current output is configured and there is no load on the output
- by a problem in the FBox (this probelm is observed very rarely)
If the problem is not caused by an incorrect configuration of the FBox or by missing power supply of the module, please download and install the latest version of the FBoxes (V 2.6.100) from the support site.
After the installation of this library, please execute a build and download the project.
PG5 2.0.110 does contain the correct library.
Replacement possibilities for PCD2.W5x0 and PCD3.W5x0 modules (FAQ #101151)
In 2009 the combined analogue input and output modules PCD2.W5x0 and PCD3.W5x0 will be discontinued. This FAQ suggests possible replacement modules depending on the measured/given signals and the required resolution.
Replacement modules for PCD2/3.W5x0
The table below contains possible replacement modules for the discontinued PCD2.W1xx modules (all PCD2.W1xx had 4 input channels and 12 bit resolution).
Module Characteristics Replacement Characteristics Remark W500 2 input 12 bit; 0..10 V, ±10 V
2 outputs 12 bit; 0..10V, ±10 V
W525 4 inputs 14 bit;
- 0..10 V
- or 0..20 mA / 4..20 mA
- or Pt1000, Pt500 or Ni1000
2 outputs 12 bit;
- 0..10 V
- or 0..20 mA / 4..20 mA
galvanic separation W325 7 inputs 12 bit; ±10 V galvanic separation W625 6 outputs 10 bit; ±10 V galvanic separation W610 4 outputs 12 bit; ±10 V, 0..20mA W510 2 input 12 bit; 0..20 mA, -20..0 mA, ±20 mA
2 outputs 12 bit; 0..10V, ±10 V
W525 4 inputs 14 bit;
- 0..10 V
- or 0..20 mA / 4..20 mA
- or Pt1000, Pt500 or Ni1000
2 outputs 12 bit;
- 0..10 V
- or 0..20 mA / 4..20 mA
galvanic separation W625 6 outputs 10 bit; ±10 V galvanic separation W610 4 outputs 12 bit; ±10 V, 0..20mA
- The W5x0 modules can not be replaced by other analogue input/output modules without adapting the user program of the according PCD! The FBoxes (or the IL code) for reading the analogue inputs need to be replaced with the FBox/IL code for the replacement module!
- There is no replacement for the ±20 mA input of the PCD2.W510 due to a very low demand. In case such a signal is to be measured we recommend applying an external converter of this input signal.
Repair service for PCD2/3.W5x0
PCD2/3.W5x0 modules will be repaired by Saia Burgess Controls until end of 2014.
PCD3.W800: how to detect if an output channel is in forced state (FAQ #101063)
The hardware manual does not explain how to read the state of the auto/manual switch of the PCD3.W800 modules, the relevant information can be found in the online help of the PCD3.W800 FBox.
The state of the switches can be detected in the Error register output of the FBox, bit 0 is for channel 0, bit 4 for channel 1, bit 8 for channel 2.
A state 0 means auto, a state 1 means manual (forced output).
Which module to use for Pt100 / Ni100 measurements? (FAQ #101032)
PCD2.W745 and PCD3.W745 are by far the best choice, other modules (e.g. PCD2/3.W350 or PCD2/3.W220Z18) are only to be used when accuracy does not matter.
The resistance of Pt 100 and Ni 100 elements is low compared to the resistance of the line connecting the sensor element to the PCD. When using 2 wire mode (e.g. with PCDx.W350) the resistance of the lines add to the resistance of the element, which means that the measured temperatures are always too high. Worse than that the line resistance has as well a temperature coefficient and there is no way to compensate for that in 2 wire mode.
Best choice of module
The answer to this issue is the 4 wire mode as supported by the PCDx.W745. A pair of lines is used to supply the element, another pair of lines to measure the voltage drop over the element. Thanks to this the resistance of the line and its temperature coefficient do no longer matter. Another advantage of the PCDx.W745 is the 16 bit resolution, which is advantageous for temperature measurements.
The effect described in the first paragraph is as well present with Pt1000 / Ni1000 elements, but 10 times weaker. For many applications it is therefore adequate to use 2 wire mode, compensate the offset with a subtraction and forget about the temperature effect of the line when using Pt1000 / Ni1000. If you have a choice avoid elements with low resistance like Pt 100 / Ni 100 / Balco 500.
Can PCD2/3.W3x5 module measure "overrange values"? (FAQ #100955)
Yes, the intelligent analogue modules PCD2.W3x5 and PCD3.W3x5 are able to read an "overrange value" of up to 110%.
As result, it is possible reading e.g. the digital value 4100 instead of 4095 (maximal 12 bit value). Of course, this is only the case if the measured signal is higher than the specified value (e.g. 10.1 Volt or 20.1 mA).
Can I switch off the overrange measurement?
Yes, if no overrange value is desired, the module can be configured for not reading the override values. This is done in the FBox by selecting the option "0..100%" in the parameter "Value range".
If the analogue input module is used on a PCD3.T760, the according parameter is called "Under-/Overflow avoidance" and needs to be switched on, if no overrange value is desired.
While the default FBox option is "0..100%" (no overrange), the default option when used on a PCD3.T760 is measuring the "Under-/Overflow".
On the Profibus-DP or Profi-S-I/O master it isn't possible to read or write registers with address > 4095 from the slave (FAQ #100927)
On the master PCD the I/O mapping to Register 4096 until Register 16'383 for RIO-networks (Profibus DP or Profi-S-I/O) doesen't work on PCD3 and PCD2.M480 and PCD2.M5xx0 systems with firmware version 1.08.23.
When using addresses between 4096 to 16383 on the maser PCD for reading/writing medias of Profibus-DP / Profi-S-I/O slaves, no values can be read from these slaves. The relevant registers are not updated by the Profibus or S-I/O task in this case.
This problem does only occur with firmware versions 1.08.xx until version 1.08.31; it is therefore even possible that a project correctly runs until the firmware of the Profi-S-I/O or Profibus DP master PCD has been updated.
The reason for this behavior is an incorrect mapping on the Profibus-DP / Profi-S-I/O master done by the firmware of the CPU. This behaviour has been introduced in version 1.08.xx (pilot versions already in 1.07.xx) and is solved in version 1.08.34 and later.
Please update the firmware of your
- PCD3 to 1.10.16 or later
- PCD2.M5 to 1.10.16 or later
- PCD2.M480 to 1.08.53 or later
If this is not possible for some reason, only use adresses R 0 - R 4095 to map the modules.
Connecting "special" temperature sensors to analogue modules. (FAQ #100926)
Depending on the resistive temperature detector type and the analogue input module, various combinations are possible which are not all listed in the FBox or the manuals.
In general an analogue input module designed for measuring the resistance of an NI1000 or PT1000 sensor can also measure the resistance of e.g. an NI1000 Landis & Staefa (L&S) or an NTC10 sensors (and many more). However, the FBox does not necessarily feature the option for configuring the relevant sensor type. In this case, the digital value of the input module can be read in the mode "1:1" and based on this value, the temperature can be calculated (or more precisely: interpolated) by using the FBox "Conversion 20 point" from the FBox Family "HVC General".
The according values which are to be filled in the "Conversion 20 point" FBox can be obtained from Saia-Burgess Controls AG.
Which combinations are possible?
In general it is important that the resistance range for which the analogue input module is designed for does fit the resistance range of the sensor for the temperature range to be measured. It is even possible to apply e.g. a parallel resistance in order to shift the resistance measured to a range which can be measured by the analogue input module. Below you can find some often used combinations of analogue input modules and special tempearture sensors:
- NTC10k sensor with PCD2/3.W340 together
- NTC10kPre sensor with PCD2.W220Z02 or PCD3.W220Z03
- NTC20k Honeywell with PCD2.W220Z02 or PCD3.W220Z03
- Ni1000 L&S with large temperature range on PCD2/3.W220 or PCD2/3.W340
- Ni1000 Tk 5000 with PCD2/3.W360
- Ni200 DIN 43760 with PCD2/3.W350
- Potentiometer 1kOhm on PCD2/3.W220
- Potentiometer 2kOhm on PCD2/3.W340
- Staefa T1 with PCD2/3.W220
- QAC 31 with PCD2/3.W220
- KTY10-6 on PCD2/3.W220 or PCD2/3.W340 (temperature range -45..50°C)
Where from do I get the values for the conversion?
Please send a mail which contains the specific type of your sensor (if possible, provide the resistance table of the sensor) and the definition of the temperature range you need to measure to email@example.com.
Why is the range of analogue (current-) input modules specified as 0(4)..20 mA? (FAQ #100675)
Most sensors with current output work with a range of 4..20 mA. Nevertheless it is possible measuring the range 0..20 mA with the analogue input modules for PCD systems.
Why do the SBC input modules have a range of 0..20 mA?
One advantage of measuring the whole range of 0..20 mA is that this way also a cable break (or a defective sensor) can be detected. If a value between 0..4 mA is measured, the conclusion is that either the cable is broken or the sensor is not working correctly.
Another advantage is that one module type can be used for both ranges (0..20 mA and 4..20 mA).
Does the specified resolution apply for the 0..20 mA or for the 4..20 mA?
The specified resolution does always apply for the full range of 0..20 mA. The same resoultion is used if the input module is used for measuring 4..20 mA.
If a 12 bit input card is used, we'll have a resolution of 4095 DV (Digital Value) over the whole range 0..20 mA. One DV corresponds to 4.88 µA.
In case a range of 4..20 mA is measured the resolution will remain the same (4.88µA per DV) and the measured range of 16 mA will be divided by 3276 DV.
Of course it is still possible detecting a sensor/cable fault because the whole range 0..20 mA is measured by the module.
Analogue modules read wrong values while beeing online with PG5 (FAQ #100631)
Due to a problem in PG5 (Fupla and Watchwindow) the values read by certain analogue modules can occasionally be corrupted while beeing online with the PCD.
While beeing online with the PCD, input values of analogue input modules jump to wrong values. The problem occurs occasionally and the value shown while the error case is not predictable (but it often is always the same value). The problem occurs when beeing online with Fupla and/or the PG5 Watch Window.
When beeing online with Fupla only, the problem can disappear when viewing another Fupla page.
All analogue modules with the exception of intelligent analogue modules (W745, W720, W3x5, W525 and W6x5) can be concerned by this problem.
The reason for this problem is a problem in the "Synchronous Data View" of Fupla and the WatchWindow. When using the "Synchronous Data View" and viewing a digital input or output, PG5 automatically does read the following 31 I/Os, too. In case the addresses of an analogue module are read by this automatism, a value corruption can be the result.
Affected PG5 1.4 versions (older versions than PG5 1.4 aren't affected because the "Synchroneous Mode" was not implemented):
- PG5 1.4.100
- PG5 1.4.110
- PG5 1.4.130
- PG5 1.4.200
PG5 1.4.120 does contain a correction that avoids this problem.
This problem can be fixed by installing PG5 SP 1.4.300. The latest version of the PG5 can be found on the support site (www.sbc-support.ch) in the section "Product information" --> "Software" --> "PG5"
How to connect two-wire current converters? (FAQ #100623)
The analogue input modules for current inputs can be used together with four-wire current converters and also with two-wire current converters.
How to connect a two-wire current converter?
Usually 2-wire current converters (0..20 mA or 4..20 mA) are to be supplied with 24V. The converter itself will then limit the current according to the unit to be converted.
For this system to work the wiring scheme below needs to be applied. Note that the converter is serially connected to the input module.
Never connect the 24V directly to the input of the analogue input module because this could damage the input module!
Shall the terminal 16 of the PCD2/3.W745 be connected to ground? (FAQ #100604)
The analogue input modules PCD2.W745 and PCD3.W745 do have a terminal 16 (GND) which is not documented in version 1 of the manual 27/796.
Reason for the terminal 16 (GND)
As the W745 is galvanically separated (the separation is from all terminals against the PCD I/O bus and not between the terminals) there is no defined ground level of the terminals. This leads to floating levels on the terminal side. In order to eliminate this floating level the terminal 16 is present for a connection against the common sensor ground.
When do I have to connect terminal 16 to GND?
- The terminal 16 should be connected to ground if no sensor does have an internal connection to the ground level. This is the case for common TC sensor or Pt/Ni sensors. In this case, connect the terminal 16 to ground.
- The terminal 16 should not be connected to ground if one or more sensors do have an own connection to ground (which is not recommended).
The galvanic separation of the module is applied between the I/O bus of the PCD and the terminals of the W745. The terminals themselves are not separated galvanically agains each other (the GND of the inputs is connected on the module). The separation is designed for a voltage of 500 VDC.
How to configure the PCD3.W800 and A810 on an RIO Module PCD3.T760? (FAQ #100570)
When using the modules PCD3.W800 and A810 on T760, it is necessary to know the address mapping which may be different that when they are used on a PCD3.Mxxx processor or on a LIO module (PCD3.Cxxx)!
In PG5 when the SIO or DP file is build, network variables are created in a new tag of the symbols editor. Those network variables (flags and registers) are at disposal in the different editors.
Attached the example done with PG5 1.4 110 contains a SIO file and a Fupla file!
PCD3.A810 on RIO module PCD3.T76
When using PCD3.W800 on a PCD3.T760 the (inputs) addresses are swapped compare to when used on a PCD3.Mxxx or Cxx
Data read: the bits 0..3 are: Switch: Output 0..3 (0=Auto, 1=Man)
Data read: the bits 8..11 are: Status Output 0..3
Data write: Output 0..3Address + BAData read (inputs)Data write (outputs)0Switch: Output 0 (0=auto;1=man)Output 01Switch: Output 1 (0=auto;1=man)Output 12Switch: Output 2 (0=auto;1=man)Output 23Switch: Output 3 (0=auto;1=man)Output 345678State: Output 09State: Output 110State: Output 211State: Output 312131415
PCD3.W800 on RIO module PCD3.T760
The following addresses are at disposal:
· 3 bits (flags) are used (0,4,8) to read the state of the Man/Auto switch
· 4 registers (0..3) to write the analog output value
.Address + BAData read (Inputs)Data write AO (Registers)0Switch : Output 0 (0=Auto, 1=Man)Analog Output 01Analog Output 12Analog Output 23Analog Output 34Switch : Output 1 (0=Auto, 1=Man)5678Switch : Output 2 (0=Auto, 1=Man)9101112131415
Are the modules PCD3.W800, PCD3.A810 and PCD3.A860 supported by the PCD3.T760? (FAQ #100504)
Yes they are and starting in PG5 1.4 these modules are included in the S-Net Configurator by default. When using PG5 1.3 an import of a recent version of the GSE (or GSD) file is necessary. The firmware of the PCD3.T760 must be V 1.019 or later.
In the S-Net Configurator of PG5 1.3 (DP or S-I/O) the modules PCD3.W800, PCD3.A810 and PCD3.A860 are not implemented.
The mentioned modules are not implemented because at the time PG5 1.3 has been released the modules have not been available.
Upgrade the firmware of the PCD3.T760 to V 1.019 or later and with right-mouse-click on the T760 device in the SIO-configurator 'Remove Device ...' , delete the actual GSE-file. Then, import the new GSE file into the S-Net Configurator. Note that the new GSE file has to be named exactly 'PCD3.T760'. If the name is different, the S-I/O configurator will not use the new version. Old projects will also work correctly with the new GSE file.
What is the reason for the error "underflow" of the PCDx.W745? (FAQ #100499)
In case a thermocouple sensor is connected with the wrong polarity, the FBox (or the FB) will indicate this with the error "underrange" or "underflow".
The problem most likely occurs in higher temperature ranges as the voltage measured at room temperature is nearly =0. Therefore it is possible that the problem doesn't occur at room temperature (also the temperature measured is not accurate in this case, no error message is indicated).
This FAQ applies to the PCD2.W745 as well as for the PCD3.W745.
Frozen PCD2/3.W3x5 and PCD2/3.W6x5 modules (FAQ #100475)
From a series produced in 2005 (Date Code "05xx" and FW-Version "020"), a small percentage of modules of the mentioned types show the following problem:
- Input modules: the output values of the FBox freeze, the LED and diagnose output of the FBox indicate “no response”
- Output modules: the output values of the module freeze, the LED and diagnose output of the FBox indicate “no response”
If the problem does not appear within the first five minutes, it does not appear at all. If you have affected units, please return them for repair via your local SBC representative.
Negative values from PCD3.T760 are not interpreted correctly on the PCD (FAQ #100466)
When measuring e.g. the temperature of a Pt1000 sensor with a W-module mounted on a PCD3.T760, the sensor type can be configured in the SBC Network Configurator. If this is done this way, negative temeratures are not interpreted correctly on the PCD. Instead of negative values, very high values around 65000 are shown.
The temperature values read from the PCD3.T760 aren't negative but very high (around 65000). Positive values read are interpreted correctly. All modules that do offer the possibility of reading temperature values are affected (PCD3.W220, PCD3.W340, PCD3.W350, PCD3.W360, PCD3.W745).
The reason for this phenomenon is the fact that the values transmitted over Profibus DP or Profi-S-I/O are signed 16-bit values. These values are copied directly into the signed 32-bit registers of the PCD. Due to the lack of a transfer function that converts the negative values (and copies the sign bit from the 16th to the 32th bit), the negative 16-bit values aren't correctly interpreted when copied into a 32-bit register.
An according transfer function has been implemented in the firmware of recent PCD systems.
For configuring this transfer function, select the checkbox "Signed" in the Profi-S-I/O (or Profibus DP) Network Configurator as in the screenshot shown.
The minimal PG5 version to use this functionality is PG5 1.4.120.
The first pilot firmware version supporting the discussed transfer function is $27 for PCD3 and $29 for PCD2.M480.
Firmware versions supporting the transfer function (systems not listed in this table do not support the transfer function mentioned):
PCD System minmal Firmware version PCD1.M1350E3 PCD2.M1500E3 PCD2/4.M1700E3 PCD2.M480030 PCD2.M5xx01.08.19 PCD3.Mxxx0031
On other systems than the ones listed above the following workarounds are possible:
- Reading the raw values from the W-modules (1:1) and then converting these values e.g. in Fupla by using the FBox "20-point-conversion". A table for this conversion accroding to the applied module and senser type can be requested from firstname.lastname@example.org
- Converting the read temperature values at the very beginning of the COB 0. Because the read values are copied to the PCD registers always right before the start of the execution of the COB 0, this will convert the values always just after the writing into registers. All following COBs created by the user will have the correct values read from the PCD3.T760. An example code for this method is attached to this FAQ. This file also contains guide how to introduce this function into an existing project.
Sampling time of PCD2/3.W6x5 modules (FAQ #100395)
In contrast to the conventional analogue modules (e.g. the W600), the DAC (Digital to Analogue Convertor) of the PCD2/3.W6x5 is not accessed directly over the internal I/O bus of the PCD. The command is first interpreted by the module's micro controller and then cyclically passed to the DAC.
Reason for the new function principle
The employment of a µC on the module can decreases the load of the PCD's main CPU because the conversion and linearization of the output value is done directly on the I/O module (before writing it to the DAC). Because of the fact that the modules are equipped by a µC, they are called "intelligent analogue modules".
Handling by the user program
The command sequence for an analogue output value is too long for writing directly onto the internal I/O bus. Therefore specific FBoxes were created (also handling the module initialisation, value range checking and the interpretation of possible error flags from the module). The execution time of the FBox on a PCD2.M170 varies from 0.8 ms to 3.8 ms (depending on the stretch factor). The output value will be overtaken by the module's µC at the very ending of the execution of the code on the PCD.
Cycle time on the module
The µC of the modules PCD2/3.W605, PCD2/3.W615 and PCD2/3.W625 executes the following tasks cyclically:
- Comparison whether new values were sent by the PCD
- Calculation of the digital values to be sent to the DAC out of the value in user units
- Writing the digital values to the DAC
The µC cycle time of the W6x5 modules is firmware depending. While it is around 4 ms with FW version 020, it is around 2 ms with FW version 021 and above. (The module's firmware version is printed on a sticker on the module, holding 3 digits)
Since the cycle time of the PCD main CPU and the µC of the W6x5 are asynchronous, it may take up to twice the cycle time from the time the value was sent to the module until it written to the DAC. Also consider the output filter that delays the real output signal by some more µs.
The communication between the internal PCD I/O bus and the µC of the module influences the cycle time only slightly.
The screenshot below visualizes the execution time of the FBox part of one Channel (upper graph) and the output signal of the W6x5 (lower graph, 2...3.7 ms after executed command on the PCD). This graphs were recorded with a PCD2.M170 and a PCD2.W625 FW 021.
Note regarding the TI
In the TI (up to version 5), a sampling rate of 2 ms is declared. This is not correct for modules equipped with FW version 020.
In the german version of the TI, a vaque translation of the sampling rate (translated to "Gesamtwandlungszeit") can cause missinterpretation.
How to configure a PCD3.W745 on a PCD3.T760? (FAQ #100214)
In PG5 SP1.2.130 the analogue module PCD3.W745 isn't implemented. To be able to configure the PCD3.W745 on a PCD3.RIO the latest *.gsd file is required.
The corresponding *.gsd file is available on the Support Site under "Browse by product Code/PCD3/Txxx/Txxx".
Ad the new modules using the funtion "Ad device" of the menu "Library" of the SNet32.
Why do PCD3.Wxxx input modules placed on an extension modules PCD3.Cxxx not work properly? (FAQ #100054)
This phenomenon could be caused by a missing power supply or if the current consumption of the I/O modules exceeds the maximum supply of the extension module. A missing jumper inside the PCD3.C200 can lead to this situation, too!
Analogue input modules PCD3.Wxxx placed on or after a PCD3.C200 do not work correctly. They give unstable, changing or/and wrong values. If placed on a high address, it isn't possible to access the I/Os.
This phenomenon could be caused by a missing power supply or if the current consumption of the I/O modules exceeds the maximum supply of the extension module.
It could also be that the 24V power supply of the PCD3.C200 is interrupted by a missing jumper (the PCD3.C200 has a jumper inside to activate the 24 V power supply). If this jumper is missing the PCD3.C200 is acting as a PCD3.C100!
First verify whether the maximum current for your I/O constellation on the LIO is sufficient. This can be done by
- the "Useful Excel sheet" to calculate the power consumption which can be found in the PCD3.Mxxx section of the support site
- or with the Device Configurator (from PG5 1.4.300 or PG5 2.0)
If the power consumption is not exceeded, open the cover of the PCD3.C200 and check if the jumper situated in the top right corner of the print is set.