General Information To Modbus Communication Via A Plc Etc - Danfoss EKD 316 Manual

Manual Superheat controller type EKD 316
Survey and function (continued)
Manual control of outputs
For service purposes the ETS-output and alarm relay outputs can be forced
However, only when regulation has been stopped.
OFF: No override
1: Manual control via o45 is enabled
2: The alarm relay releases so that there is a connection between 24 and 25 (= alarm)
3: The alarm relay picks up so that there is a connection between 25 and 26 (= no alarm)
Manual control of the ETS valve
The valve's opening degree can be set manually.
However, it does require "o18" to be set to "1", "2" or "3".
This function must only be used for manual operation. It must not be used for external
control.
Working range for pressure transmitter
Depending on the application, a pressure transmitter with a given working range is
used.
For the range of (-1 to 12 bar), the min. value is set to -1 bar.
For the range of (-1 to 12 bar), the max. value is set to 12 bar.
Selection of control algorithm
Depending on the application, control can be carried out based on different param-
eters.
The two possibilities are shown in section "Type of regulation".
1=normal control (single loop)
2=with inner loop regulation and S4 temperature less T0 (double loop)
Note:
* After o56 is changed, the controller must be switched off and powered up again.
Refrigerant setting
Before refrigeration can be started, the refrigerant must be defined. You can select the
following refrigerants:
1 = R12 10 = R503 19 = R404A
2 = R22 11 = R114 20 = R407C
3 = R134a 12 = R142b 21 = R407A
4 = R502 13 = User-defined 22 = R407B
5 = R717 14 = R32 23 = R410A
6 = R13 15 = R227 24 = R170
7 = R13b1 16 = R401 25 = R290
8 = R23 17 = R507 26 = R600
9 = R500 18 = R402A 27 = R600a
( Warning: Incorrect selection of refrigerant may cause damage to the compressor).
Service
A number of controller values can be printed for use in a service situation
Read value of external current signal/voltage signal (Ext.Ref.)
Read status of input DI (start/stop input)
Read the temperature at the S2 sensor
Read superheat
Read the control's actual superheat reference
Read the valve's opening degree
Read evaporating pressure
Read evaporating temperature
Read the temperature at the S4 sensor
Operating status
The controller's operating status can be called forth by a brief (1s) activation of the
upper button. If a status code exists, it will be shown. (Status codes have lower priority
than alarm codes. This means that status codes cannot be seen if there is an active
alarm code.
The individual status codes have the following meanings:
S10: Refrigeration stopped by the internal or external start/stop.
20 DKRCC.PS.RP0.A1.02/520H7142
o18 Manual ctrl
o45 Manual ETS OD%
o20 MinTransPres.
o21 MaxTransPres.
o56 Reg. type *
o30 Refrigerant
28 = R744
29 = R1270
30 = R417A
31 = R422A
32 = R413A
33 = R422D
34 = 427A
35 = R438A
R36 = Opteon XP10
37 = R407F
Service
u06 Analogue input
u10 DI
u20 S2 temp.
u21 SH
u22 SH ref.
u24 OD%
u25 Evap. pres. P
e
u26 Evap.Press.T
e
u27 S4 temp.
-- DO1 Alarm
Read status of alarm relay
EKC State
(0 = regulation)
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©Danfoss A/S (AC-MCI / sw), 2014-03
Manual Superheat controller type EKD 316
Appendix II
General information to MODBUS
communication via a PLC etc.
* Baudrate : 19200
* EKD Address : 240
* Polarity A-A and B-B
* Termination with 120 ohm resistor
Some parameters have what is called a "config lock". This means
that they can only be changed when the main switch of the EKD
is set to OFF (r12 = 0). This applies for instance to the type of
refrigerant (o30). So if you want to change the refrigerant, the
main switch (r12) must first be set to 0, then the refrigerant type
(o30) can be changed.
Example:
EKD 316 as simple ETS valve driver function with the following
settings:
ƒ PNU 117 [0] r12 Main switch = 0
ƒ PNU 2075 [1] o18 Manual mode
ƒ PNU 2064 [OD% ] o45 Manual ETS OD% (replace 0-10V signal)
ƒ PNU 3032 [262] n37 Max. steps 2620
ƒ PNU 3033 [250] n38 Steps pr. sec 250
ƒ EKD 316 address : 240
ƒ PNU 2064 will go back to 0% at power off as the only one
©Danfoss A/S (AC-MCI / sw), 2014-03 DKRCC.PS.RP0.A1.02/520H7142
The following parameters require the main switch to be OFF:
n03 Valve type
n37 Max steps
n38 Max steps/sec
o03 Unit address
o30 Refrigerant
o56 Regulation type
o61 Application mode
Please refer to the manual for descriptions of these parameters.
It should be possible to change all other parameters while the unit
is running (regulation parameters etc.).
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