Added new feature to set deadband

The field SPDB can now be populated via either the substitutions file or
from inside the driver (using the motorPositionDeadband paramLib entry).

db/sinqMotor.db

@@ -41,6 +41,7 @@ record(motor,"$(INSTR)$(M)")
     field(PINI,"NO")
     field(DHLM, "$(DHLM=0)")
     field(DLLM, "$(DLLM=0)")
+    field(SPDB, "$(SPDB=0)")
     field(TWV,"1")
     field(RTRY,"0")
     field(RDBD, "$(RDBD=10e300)") # Suppress retries and overshoot stop commands
@@ -238,6 +239,27 @@ record(ao, "$(INSTR)$(M):PushDLLM2Field") {
     field(PINI, "NO")
 }
 
+# This record pair reads the parameter library value for "motorPositionDeadband"
+# and pushes it to the motor record field "SPDP". This can be used to the position
+# deadband from the hardware
+# The implementation strategy is taken from https://epics.anl.gov/tech-talk/2022/msg00464.php.
+# This record is coupled to the parameter library via motorPositionDeadband -> MOTOR_POSITION_DEADBAND.
+record(ai, "$(INSTR)$(M):SPDB_RBV")
+{
+    field(DTYP, "asynFloat64")
+    field(VAL, "$(SPDP=0)")
+    field(INP,  "@asyn($(CONTROLLER),$(AXIS)) MOTOR_POSITION_DEADBAND")
+    field(SCAN, "I/O Intr")
+    field(FLNK, "$(INSTR)$(M):PushSPDB2Field")
+    field(PINI, "NO")
+}
+record(ao, "$(INSTR)$(M):PushSPDB2Field") {
+    field(DOL,  "$(INSTR)$(M):SPDB_RBV NPP")
+    field(OUT,  "$(INSTR)$(M).SPDB")
+    field(OMSL, "closed_loop")
+    field(PINI, "NO")
+}
+
 # This record pair reads the parameter library value for "motorVeloFromDriver_"
 # and pushes it to the motor record field "VELO". This can be used to read the speed value
 # from the hardware and correspondingly update the motor record from the driver.

src/sinqController.cpp

@@ -92,6 +92,7 @@ struct sinqControllerImpl {
     int motorAcclFromDriver;
     int motorHighLimitFromDriver;
     int motorLowLimitFromDriver;
+    int motorPositionDeadband;
     int adaptivePolling;
     int encoderType;
 };
@@ -267,6 +268,17 @@ sinqController::sinqController(const char *portName,
         exit(-1);
     }
 
+    status = createParam("MOTOR_POSITION_DEADBAND", asynParamFloat64,
+                         &pSinqC_->motorPositionDeadband);
+    if (status != asynSuccess) {
+        asynPrint(this->pasynUser(), ASYN_TRACE_ERROR,
+                  "Controller \"%s\" => %s, line %d\nFATAL ERROR (creating a "
+                  "parameter failed with %s).\nTerminating IOC",
+                  portName, __PRETTY_FUNCTION__, __LINE__,
+                  stringifyAsynStatus(status));
+        exit(-1);
+    }
+
     status = createParam("MOTOR_ENABLE_MOV_WATCHDOG", asynParamInt32,
                          &pSinqC_->motorEnableMovWatchdog);
     if (status != asynSuccess) {
@@ -699,6 +711,9 @@ int sinqController::motorHighLimitFromDriver() {
 int sinqController::motorLowLimitFromDriver() {
     return pSinqC_->motorLowLimitFromDriver;
 }
+int sinqController::motorPositionDeadband() {
+    return pSinqC_->motorPositionDeadband;
+}
 int sinqController::adaptivePolling() { return pSinqC_->adaptivePolling; }
 int sinqController::encoderType() { return pSinqC_->encoderType; }
 

src/sinqController.h

@@ -315,6 +315,7 @@ class HIDDEN sinqController : public asynMotorController {
     int motorAcclFromDriver();
     int motorHighLimitFromDriver();
     int motorLowLimitFromDriver();
+    int motorPositionDeadband();
     int adaptivePolling();
     int encoderType();