Time delaying causes checksum errors in PMS5003 particulate matter data reading - arduino

Question

I'm using the default code for a PMS5003 particulate matter sensor (with the RTC time features removed for now). However, I don't want to the data output to be on a constant loop; instead, I want to collect data only at certain intervals, for example every 10 seconds or every minute. To do this, I simply added a delay line at the end of the main loop. And with even the slightest delay of 1 second, I quickly run into checksum errors, although the code works fine without the delay.
#include <SoftwareSerial.h>
SoftwareSerial pmsSerial(2, 3);
void setup() {
// our debugging output
Serial.begin(9600);
// sensor baud rate is 9600
pmsSerial.begin(9600);
}
struct pms5003data {
uint16_t framelen;
uint16_t pm10_standard, pm25_standard, pm100_standard;
uint16_t pm10_env, pm25_env, pm100_env;
uint16_t particles_03um, particles_05um, particles_10um, particles_25um, particles_50um, particles_100um;
uint16_t unused;
uint16_t checksum;
};
struct pms5003data data;
void loop() {
if (readPMSdata(&pmsSerial)) {
// reading data was successful!
Serial.println();
Serial.println("Concentration Units (environmental)");
Serial.print("PM 1.0: "); Serial.print(data.pm10_env);
Serial.print("\t\tPM 2.5: "); Serial.print(data.pm25_env);
}
//This line causes issues
delay(1000);
}
boolean readPMSdata(Stream *s) {
if (! s->available()) {
return false;
}
// Read a byte at a time until we get to the special '0x42' start-byte
if (s->peek() != 0x42) {
s->read();
return false;
}
// Now read all 32 bytes
if (s->available() < 32) {
return false;
}
uint8_t buffer[32];
uint16_t sum = 0;
s->readBytes(buffer, 32);
// get checksum ready
for (uint8_t i=0; i<30; i++) {
sum += buffer[i];
}
/* debugging
for (uint8_t i=2; i<32; i++) {
Serial.print("0x"); Serial.print(buffer[i], HEX); Serial.print(", ");
}
Serial.println();
*/
// The data comes in endian'd, this solves it so it works on all platforms
uint16_t buffer_u16[15];
for (uint8_t i=0; i<15; i++) {
buffer_u16[i] = buffer[2 + i*2 + 1];
buffer_u16[i] += (buffer[2 + i*2] << 8);
}
// put it into a nice struct :)
memcpy((void *)&data, (void *)buffer_u16, 30);
if (sum != data.checksum) {
Serial.println("Checksum failure");
return false;
}
// success!
return true;
}
I suspect that the delay is causing the sensor and the Arduino to somehow desync. I also think it could possibly have to do with poor soldering of the sensor wires (though this wouldn't explain why the sensor works perfectly without the delay). Anyone know what's causing this issue, and how I might fix it?
Thanks.