Add OPC to all SCIPPs commands.

Add SCPIPs::send/sendreceive function(s) whose job is to block until a power supply command finishes, as indicated by the Operation Complete command. This prevent the program from terminating while a command is still being processed, solving #36. I've also seen stability improvements with RS-232 mode on the Agilent PS's.

This approach is recommended by R&S. See section 4.2.1.

There are two variations of send added.

• send(const std::string& cmd): Send *OPC?" to after cmd string and blocks until a response is received. If response other than 1 is seen, error is thrown.

• command(const std::string& cmd, unsigned channel): Sends ":INST:NSEL "+channel+"" and then calls the first variation of send.

The sendreceive functions do not use *OPC? and are just a wrapper around m_com. They were added for symmetry.

All commands in SCPIPs are now done though this.

src/libPS/SCPIPs.cpp

@@ -21,7 +21,7 @@ bool SCPIPs::ping()
 
 void SCPIPs::reset()
 {
-  m_com->send("*RST");
+  send("*RST");
 
   if(!ping())
     throw std::runtime_error("No communication after reset.");
@@ -35,14 +35,12 @@ std::string SCPIPs::identify()
 
 void SCPIPs::turnOn(unsigned channel)
 {
-  setChannel(channel);
-  m_com->send("OUTPUT ON");
+  send("OUTPUT ON", channel);
 }
 
 void SCPIPs::turnOff(unsigned channel)
 {
-  setChannel(channel);
-  m_com->send("OUTPUT OFF");
+  send("OUTPUT OFF", channel);
 }
 
 void SCPIPs::setChannel(unsigned channel)
@@ -55,25 +53,22 @@ void SCPIPs::setChannel(unsigned channel)
 
   if(m_maxChannels==1) return; // No need to change channel
 
-  m_com->send("INST:NSEL " + std::to_string(channel));
+  send("INST:NSEL " + std::to_string(channel));
 }
 
 void SCPIPs::setCurrentLevel(double cur, unsigned channel)
 {
-  setChannel(channel);
-  m_com->send("CURRENT " + std::to_string(cur));
+  send("CURRENT " + std::to_string(cur), channel);
 }
 
 double SCPIPs::getCurrentLevel(unsigned channel)
 {
-  setChannel(channel);
-  return std::stod(m_com->sendreceive("CURRENT?"));
+  return std::stod(sendreceive("CURRENT?", channel));
 }
 
 void SCPIPs::setCurrentProtect(double maxcur, unsigned channel)
 {
-  setChannel(channel);
-  m_com->send("CURRENT " + std::to_string(maxcur));
+  send("CURRENT " + std::to_string(maxcur), channel);
 }
 
 double SCPIPs::getCurrentProtect(unsigned channel)
@@ -83,26 +78,22 @@ double SCPIPs::getCurrentProtect(unsigned channel)
 
 double SCPIPs::measureCurrent(unsigned channel)
 {
-  setChannel(channel);
-  return std::stod(m_com->sendreceive("MEAS:CURR?"));
+  return std::stod(sendreceive("MEAS:CURR?", channel));
 }
 
 void SCPIPs::setVoltageLevel(double volt, unsigned channel)
 {
-  setChannel(channel);
-  m_com->send("VOLTAGE " + std::to_string(volt));
+  send("VOLTAGE " + std::to_string(volt), channel);
 }
 
 double SCPIPs::getVoltageLevel(unsigned channel)
 {
-  setChannel(channel);
-  return std::stod(m_com->sendreceive("VOLTAGE?"));
+  return std::stod(sendreceive("VOLTAGE?", channel));
 }
 
 void SCPIPs::setVoltageProtect(double maxvolt, unsigned channel)
 {
-  setChannel(channel);
-  m_com->send("VOLTAGE " + std::to_string(maxvolt));
+  send("VOLTAGE " + std::to_string(maxvolt), channel);
 }
 
 double SCPIPs::getVoltageProtect(unsigned channel)
@@ -112,8 +103,46 @@ double SCPIPs::getVoltageProtect(unsigned channel)
 
 double SCPIPs::measureVoltage(unsigned channel)
 {
-  setChannel(channel);
-  return std::stod(m_com->sendreceive("MEAS:VOLT?"));
+  return std::stod(sendreceive("MEAS:VOLT?", channel));
 }
 
+void SCPIPs::send(const std::string& cmd)
+{
+  m_com->send(cmd);
+  std::string opcreply=m_com->sendreceive("*OPC?");
+  if(opcreply!="1")
+    throw std::runtime_error("SCPI command not completed");
+}
+
+void SCPIPs::send(const std::string& cmd, unsigned channel)
+{
+  if(m_maxChannels>0)
+    { // In-range channel check
+      if(channel>m_maxChannels)
+	throw std::runtime_error("Invalid channel: "+std::to_string(channel));
+    }
+
+  if(m_maxChannels!=1)
+    m_com->send("INST:NSEL "+std::to_string(channel));
+
+  send(cmd);
+}
 
+std::string SCPIPs::sendreceive(const std::string& cmd)
+{
+  return m_com->sendreceive(cmd);
+}
+
+std::string SCPIPs::sendreceive(const std::string& cmd, unsigned channel)
+{
+  if(m_maxChannels>0)
+    { // In-range channel check
+      if(channel>m_maxChannels)
+	throw std::runtime_error("Invalid channel: "+std::to_string(channel));
+    }
+
+  if(m_maxChannels!=1)
+    m_com->send("INST:NSEL "+std::to_string(channel));
+
+  return sendreceive(cmd);
+}