Siemens RS-485 manual Operating mode

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Operating mode

The previous functions of the RWF40... are maintained (apart from memory usage).

«LOCAL»

The RWF40... can be parameterized and uploaded via the MOD bus, whereby the out-

 

puts cannot be changed. After «Power-up», the RWF40... will normally assume oper-

 

ating mode «LOCAL».

Operating mode

The RWF40... monitors cyclic bus communication via the «Dtt» parameter (bus detec-

«REMOTE SETPOINT»

tion timer). Operating mode «REMOTE SETPOINT» is active as long as the bus calls

 

within the predefined period of time. If the time limit is crossed, the RWF40... will switch

 

to operating mode «LOCAL» and continues to operate using the parameters of local

 

operation.

 

Like in operating mode «LOCAL», the control functions of the RWF40... are maintained.

 

With regard to setpoint and switching thresholds, only «RSP» and «RHYS1...RHYS3»

 

are active. The setpoints (SP1 and SP2), the external setpoint, the weather-

 

compensated setpoint, the analog / binary setpoint shift and the associated changeover

 

functions are not available.

 

After the controller’s «Power-up», setpoint «SP1» and switching thresholds

 

«Hys1...Hys3» will be copied to RAM as remote parameters in a one-time operation.

 

These remote parameters can then only be changed via the management system.

 

The control algorithm can be deactivated by the management system via parameter

 

«ROFF=1». In that case, the RWF40... will switch the burner off and causes the con-

 

trolling element to travel to the fully closed position. The controller terminates manual

 

operation (analog safety shutdown).

 

Self-optimization is not possible in this operating mode.

 

The management system controls contact «RK6» (relay «K6»).

Operating mode

The RWF40... monitors cyclic bus communication via the «Dtt» parameter (bus detec-

«FULLY REMOTE»

tion timer). Operating mode «FULLY REMOTE» is active as long as the bus calls within

 

the predefined period of time. If the time limit is crossed, the RWF40... will switch to

 

operating mode «LOCAL» and continues to operate using the parameters of local op-

 

eration.

 

The management system switches the burner (RK1, relay «K1»), controls the actuator

 

(RK2 and RK3, relays «K2 / K3»), or defines the degree of modulation in the case of an

 

analog output, and controls contact «RK6» (relay «K6»).

 

Using parameter «ROFF=1», control of the burner and controlling element can be

 

switched off by the management system. In that case, the RWF40... deactivates the

 

burner and causes the controlling element to travel to the fully closed position.

 

Manual operation and self-optimization are not possible in this operating mode.

 

2-stage burner:

 

If, with a 2-stage burner, relay positions «RK2» and «RK3» are identical, the settings

 

are «K2 = deenergized» and «K3 = energized» (closing).

 

The analog output is set as follows, depending on the relay positions «RK2» and

 

«RK3»:

 

K2 = energized, K3 = deenergized ￿ analog output = 10 V or 20 mA

 

K2 = deenergized, K3 = energized ￿ analog output = 0 V or 0 / 4 mA

 

Setting the «RY» by the management system has no impact.

 

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Siemens Building Technologies

CC1A7865.1en

HVAC Products

31.10.2002

Image 13
Contents 31.10.2002 Master-slave principleNot Transmission mode RTUDevice address Reply by the slave Communication sequenceBaud rate 600 813 19.200 406Time sequence Data query sequenceCommunication during the slave’s internal handling time Communication during the slave’s response timeSlave address Fault handlingFunction code Data fieldCRC = SHR CRC Checksum CRC16Reply CRC16 = Following functions for the device will be availableWriting 1 word Reading n wordsWriting n words Instruction Example Write switch-on threshold Hys1 = Word address =Reply AddressAccess Parameter Address Data Access Parameter Value range DefaultAddress tables REM TempRoff SetpointDevice state Address Data type Access Parameter«FULLY REMOTE» SPR Description of operating modesRemote RK1 Operating mode Control strategy for Dependent switchingFloating output with Modulating burner