Allow disabling the setting of the controller's position, which can b…

…e useful for axes with absolute encoders

acsMotionApp/Db/Makefile

@@ -28,6 +28,7 @@ DB += SPiiPlusRealVar.db
 DB += SPiiPlusProgram.db
 DB += SPiiPlusAxisExtra.db
 DB += SPiiPlusFeedback.db
+DB += SPiiPlusDisableSetPos.db
 DB += SPiiPlusTest.db
 
 #----------------------------------------------------

acsMotionApp/Db/SPiiPlusDisableSetPos.db

@@ -0,0 +1,16 @@
+record(bo,"$(P)$(M):disableSetPos") {
+    field(DESC, "Disable set position")
+    field(DTYP, "asynInt32")
+    field(OUT,  "@asyn($(PORT),$(ADDR))SPIIPLUS_DISABLE_SET_POS")
+    field(ZNAM, "Off")
+    field(ONAM, "On")
+    field(VAL,  1)
+    field(PINI, "YES")
+}
+
+# Also tell autosave to never restore the position, which is redundant
+# NOTE: this only takes effect if RSTM hasn't been autosaved yet
+record(motor,"$(P)$(M)") {
+    field(RSTM, "Never")
+}
+

acsMotionApp/src/SPiiPlusDriver.cpp

@@ -98,6 +98,8 @@ SPiiPlusController::SPiiPlusController(const char* ACSPortName, const char* asyn
 	createParam(SPiiPlusHomingOffsetNegString,            asynParamFloat64,   &SPiiPlusHomingOffsetNeg_);
 	createParam(SPiiPlusHomingCurrLimitString,            asynParamFloat64,   &SPiiPlusHomingCurrLimit_);
 	//
+	createParam(SPiiPlusDisableSetPosString,              asynParamInt32, &SPiiPlusDisableSetPos_);
+	//
 	createParam(SPiiPlusTestString,                       asynParamInt32, &SPiiPlusTest_);
 
 	// Initialize this variable to avoid freeing random memory
@@ -856,11 +858,23 @@ asynStatus SPiiPlusAxis::setPosition(double position)
 {
 	SPiiPlusController* controller = (SPiiPlusController*) pC_;
 	asynStatus status;
+	int disableSetPos;
 	std::stringstream cmd;
+	static const char *functionName = "setPosition";
 
-	// The controller automatically updates APOS and FPOS when RPOS is updated 
-	cmd << "SET RPOS(" << axisNo_ << ")=" << (position * resolution_);
-	status = controller->pComm_->writeReadAck(cmd);
+	controller->getIntegerParam(axisNo_, controller->SPiiPlusDisableSetPos_, &disableSetPos);
+
+	if (!disableSetPos)
+	{
+	  // The controller automatically updates APOS and FPOS when RPOS is updated 
+	  cmd << "SET RPOS(" << axisNo_ << ")=" << (position * resolution_);
+	  status = controller->pComm_->writeReadAck(cmd);
+	}
+	else
+	{
+	  asynPrint(pC_->pasynUserSelf, ASYN_TRACE_ERROR, "%s:%s: Changing the position of axis %i is disabled; Ignoring requested position: %lf\n", driverName, functionName, axisNo_, (position * resolution_));
+	  status = asynError;
+	}
 
 	return status;
 }

acsMotionApp/src/SPiiPlusDriver.h

@@ -141,7 +141,9 @@
 #define SPiiPlusHomingOffsetNegString          "SPIIPLUS_HOMING_OFFSET_NEG"
 #define SPiiPlusHomingCurrLimitString          "SPIIPLUS_HOMING_CURR_LIMIT"
 //
-#define SPiiPlusTestString                      "SPIIPLUS_TEST"
+#define SPiiPlusDisableSetPosString            "SPIIPLUS_DISABLE_SET_POS"
+//
+#define SPiiPlusTestString                     "SPIIPLUS_TEST"
 
 struct SPiiPlusDrvUser_t {
     const char *programName;
@@ -286,6 +288,8 @@ class epicsShareClass SPiiPlusController : public asynMotorController
 	int SPiiPlusHomingOffsetNeg_;
 	int SPiiPlusHomingCurrLimit_;
 	//
+	int SPiiPlusDisableSetPos_;
+	//
 	int SPiiPlusTest_;
 	#define LAST_SPIIPLUS_PARAM SPiiPlusTest_
 

iocs/acsMotionIOC/iocBoot/iocAcsMotion/AcsMotion.substitutions

@@ -45,6 +45,21 @@ pattern
 {pm1:,  8,    2000,      2000, ACS1,    7,     2.0,    4}
 }
 
+### Uncomment the following to disable setting the position for axes with absolute encoders
+#!file "$(TOP)/db/SPiiPlusDisableSetPos.db"
+#!{
+#!pattern
+#!{M,   PORT, ADDR}
+#!{m1,  ACS1,    0}
+#!{m2,  ACS1,    1}
+#!{m3,  ACS1,    2}
+#!{m4,  ACS1,    3}
+#!{m5,  ACS1,    4}
+#!{m6,  ACS1,    5}
+#!{m7,  ACS1,    6}
+#!{m8,  ACS1,    7}
+#!}
+
 file "$(TOP)/db/SPiiPlusAxisExtra.db"
 {
 pattern