Convertion to Python to Codesys
The PI-Plate has manufactures devices that can be used with the Raspiberry-PI. The objective of this project would not stop at just the relay plate, but also incorporate other Pi-Plate devices. The Device driver will be a child of the SPI master and have 7 slots for Pi-Plate devices.
Pi-Plates
Data Acquisition Plate with Generator Capabilities
Data Acquisition Plate
Tinker Plate, Mix of Data Acquisition and inputs
Relay Control
Temperature Measurement
Motion Control
https://pi-plates.com/pi-plates-catalog/
The relay plate has 7 relays on the plate. Looks like it is because of size and cost constraints. Stacking the plates will allow for 49 relays. Which is plenty for most projects and there is always the possibility of stringing together multiple Rasp-PIs via ethercat. Each relay will be mapped to a variable so true will be on and false will be off.
RELAY Control Functions
* relayON(addr,relay) - turns on (closes) the specified relay
* relayOFF(addr,relay) - turns off (opens) the specified relay
* relayTOGGLE(addr,relay) - "toggles" state of specified relay. If relay is on, this command will turn it off. If relay is off, this command will turn it on. Use this command to blink a lamp off and on.
* relayALL(addr,value) - used to control the state of all relays with a single command. "value" is a 7 bit number with each bit corresponding to a relay. Bit 0 is relay 1, bit 1 is relay 2, and so on. To turn all the relays on at once, use the number 127 for the value.
* relaySTATE(addr) - Returns a 7-bit number with the current state of each relay. Bit 0 is relay 1, bit 1 is relay 2, and so on. A "1" in a bit position means that the relay is on and zero means that it's off.
LED Control Functions
* setLED(addr) - turn on the LED
* clrLED(addr) - turn off the LED
* toggleLED(addr) - if LED is on, turn off. If LED is off, turn on.
System Level Functions
* getID(addr) - return Pi-Plate descriptor string
* getFWrev(addr) - return FW revision in byte format
* getHWrev(addr) - return HW revision in byte format
* getPMrev() - returns revision of python module
* getADDR(addr) - return address of pi-plate. Used for polling available boards at power up.
* RESET(addr) - set RELAYplate to power-on state. Turns all relays off. **
I am going to focus on
RelayAll
setLED
clrLED
getFWrev
getHWrev
RESET
- Python Code
def getHWrev(addr):
global RELAYbaseADDR
VerifyADDR(addr)
resp=ppCMDr(addr,0x02,0,0,1)
rev = resp[0]
whole=float(rev>>4)
point = float(rev&0x0F)
return whole+point/10.0
def getFWrev(addr):
global RELAYbaseADDR
VerifyADDR(addr)
resp=ppCMDr(addr,0x03,0,0,1)
rev = resp[0]
whole=float(rev>>4)
point = float(rev&0x0F)
return whole+point/10.0
def relayALL(addr,relays):
VerifyADDR(addr)
assert ((relays>=0) and (relays<=127)),"Argument out of range. Must be between 0 and 127"
ppCMDr(addr,0x13,relays,0,0)
def ppCMDr(addr,cmd,param1,param2,bytes2return):
global RELAYbaseADDR
arg = list(range(4))
resp = []
arg[0]=addr+RELAYbaseADDR;
arg[1]=cmd;
arg[2]=param1;
arg[3]=param2;
GPIO.output(ppFRAME,True)
null=spi.xfer(arg,300000,60)
#null = spi.writebytes(arg)
if bytes2return>0:
time.sleep(.0001)
for i in range(0,bytes2return):
dummy=spi.xfer([00],500000,20)
resp.append(dummy[0])
time.sleep(.001)
GPIO.output(ppFRAME,False)
time.sleep(.001)
return resp
**Codesys Code:**
FB_Relay_Plate
//Globals
Hardware_Version : BYTE;
Firmware_Version : BYTE;
Relay_Plate_Address : BYTE; //0 to 7 Assigned by slot address?
Relay_States : BYTE; //0 to 127, Bit 0 = Relay 0, Bit 7 = Relay 7
Led_State : BOOL; //True = On, False = Off
Previous_State : BYTE;
End
VAR CONSTANT
Relay_Base_Address : BYTE := 24;
Frame_GPIO : BYTE := 25;
PPINT : BYTE := 22;
END_VAR
Intialize
Method Set_Address
Method Get_Hardware_Version : BYTE;
Method Get_Firmware_Version : BYTE;
Cyclic Calls
METHOD Set_IO
VAR
Previous_Relay_State : BOOL;
Previous_LED_State : BOOL;
END_VAR
Case of iState
Set_Relays: IF Previous_State <> Relay_States
Relays_Set:= Write_Data(Relay_Plate_Address,0x13,Relay_States,0,0);
Previous_State := Relay_States;
Else
Relays_Set := true;
End_IF
If Relays_Set = True Then
iState := Set_Leds;
End_IF
Set_Leds :
Method Write_Data : BOOL;
VAR_INPUT
Address : BYTE;
Command : BYTE;
Parameter_1 : WORD;
Parameter_2 : WORD;
END_VAR
VAR
abyTxBuffer: ARRAY [0..2] OF BYTE;
abyRxBuffer: ARRAY [0..2] OF BYTE;
END_VAR
abyTxBuffer[0] := Relay_Base_Address + SHL(byHardwareAddress, 1); //SPI_WRITE_CMD;
abyTxBuffer[1] := byPort;
abyTxBuffer[2] := byValue;
Write_Data := transfer(pabyTxBuffer:=ADR(abyTxBuffer) , pabyRxBuffer:=ADR(abyRxBuffer) , udiLen:=3 , uiDelayus:=5 );
IF NOT Write_Data THEN
_iState := 1000;
END_IF